Dogs have been closely associated with human being for years. Dogs play the roles of pets and guards. There are more than 100 breeds of dogs with varying sizes, shapes and colors. Bulldog, Beagle, Dachshund, poodle, Boxer, Pug, Doberman, Pomeranian and Dalmatian are some of the well known breeds.
Dogs are shortsighted. They cannot distinguish colors. They see the world in shades of grey. Though the eye sight is poor compared to man, their sense of smell is thousand times better than that of humans. They normally identify the locations traversed by smelling. The acute sense of smelling power makes them suitable for performing the duties of sniffers. Trained dogs can identify explosives, drugs and culprits. One sniff is sufficient for a trained dog to identify the drugs packed and hidden even in tins.
Our nasal cavity has a yellowish are of around 250 Sq. mm. This area contains millions of hair like cells, called chemo-receptors, which are sensitive to smell. Due to the presence mucus, the area always remains wet. These receptors are connected to the olfactory bulb in the brain. When the molecules from the object reach the receptors, they get activated and signals are sent to brain through nerves. Each receptor responds to a particular smell.
The sense of smelling is directly proportional to the size of the olfactory bulb. The olfactory bulb of a dog is much bigger than that of ours, making them powerful smellers. Further, the nasal cavity of a dog is wetter than that of us which also aids better sensing of smell.
Smelling power of dogs is utilized in identifying culprits, locating missing persons and hunting. World over, dogs find their place in police force. German Shepherds and Belgian Malinois are the two most common breeds employed in police force. Beagles are experts in identifying explosives while Bernese Mountain dogs are specialists at locating missing persons. Rin Tin Tin, Mattie, Cloud II and Appollo are some of the world famous police dogs.